Low molecular weight hydroxyaminomethylphosphonates have been described in the literature as seen by the following publications:
1. M. P. Osipova et al., Deposite Doc. SPSTL 232 khp-D80 (USSR); Chem. Abst. 97, 110110 (1982); PA0 2. K. A. Petrov et al., Zh. Obshch. Khim, 49, 590 (1979); PA0 3. M. S. Skorobogatova et al., Izv. Akad. Nauk. SSSR, Ser. Khim. 1979, 1867; PA0 4. A. Muktarov et al., Izv. Akad. Nauk. SSSR, Ser. Khim. 1976, 2816; PA0 5. A. Alberti et al., Tetrahedron, 40, 4955 (1984); PA0 6. J. M. J. Tronchet et al., Carbohydrate Research, 136, 375 (1985); PA0 7. A. Vasella et al., Helv. Chim. Acta, 68, 1730 (1985); and PA0 8. Y. Yamada et al., Tetrahedron Letters, 29, 663 (1988). PA0 2,6-di-tert-butyl-4-methylphenol PA0 2-tert.butyl-4,6-dimethylphenol PA0 2,6-di-tert-butyl-4-ethylphenol PA0 2,6-di-tert-butyl-4-n-butylphenol PA0 2,6-di-tert-butyl-4-i-butylphenol PA0 2,6-di-cyclopentyl-4-methylphenol PA0 2-(.alpha.-methylcyclohexyl)-4,6-dimethylphenol PA0 2,6-di-octadecyl-4-methylphenol PA0 2,4,6-tri-cyclohexylphenol PA0 2,6-di-tert-butyl-4-methoxymethylphenol PA0 2,6-di-tert-butyl-4-methoxyphenol PA0 2,5-di-tert-butyl-hydroquinone PA0 2,5-di-tert-amyl-hydroquinone PA0 2,6-diphenyl-4-octadecyloxyphenol PA0 2,2'-thio-bis-(6-tert-butyl-4-methylphenol) PA0 2,2'-thio-bis-(4-octylphenol) PA0 4,4'-thio-bis-(6-tert-butyl-3-methylphenol) PA0 4,4'-thio-bis-(6-tert-butyl-2-methylphenol) PA0 2,2'-methylene-bis-(6-tert-butyl-4-methylphenol) PA0 2,2'-methylene-bis-(6-tert-butyl-4-ethylphenol) PA0 2,2'-methylene-bis-[4-methyl-6-(.alpha.-methylcyclohexyl)-phenol] PA0 2,2'-methylene-bis-(4-methyl-6-cyclohexylphenol) PA0 2,2'-methylene-bis-(6-nonyl-4-methylphenol) PA0 2,2'-methylene-bis-[6-(.alpha.-methylbenzyl)-4-nonylphenol] PA0 2,2'-methylene-bis-[6-(.alpha.,.alpha.-dimethylbenzyl)-4-nonylphenol] PA0 2,2'-methylene-bis-(4,6-di-tert-butylphenol) PA0 2,2'-ethylidene-bis-(4,6-di-tert-butylphenol) PA0 2,2'-ethylidene-bis-(6-tert-butyl-4-isobutylphenol) PA0 4,4'-methylene-bis-(2,6-di-tert-butylphenol) PA0 4,4'-methylene-bis-(6-tert-butyl-2-methylphenol) PA0 1,1-bis-(5-tert-butyl-4-hydroxy-2-methylphenyl-butane PA0 2,6-di-(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol PA0 1,1,3-tris-(5-tert-butyl-4-hydroxy-2-methylphenyl)-butane PA0 1,1-bis-(5-tert-butyl-4-hydroxy-2-methylphenyl)-3-n-dodecylmercaptobutane PA0 ethyleneglycol bis-[3,3-bis-(3'-tert-butyl-4'-hydroxyphenyl)-butyrate] PA0 di-(3-tert-butyl-4-hydroxy-5-methylphenyl)-dicyclopentadiene PA0 di-[2-(3'-tert-butyl-2'-hydroxy-5'-methyl-benzyl)-6-tert-butyl-4-methylphen yl] terephthalate. PA0 1,3,5-tri-(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene PA0 di-(3,5-di-tert-butyl-4-hydroxybenzyl) sulfide PA0 3,5-di-tert-butyl-4-hydroxybenzyl-mercapto-acetic acid isooctyl ester PA0 bis-(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)dithiol terephthalate PA0 1,3,5-tris-(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate PA0 1,3,5-tris-(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate PA0 3,5-di-tert-butyl-4-hydroxybenzyl-phosphoric acid dioctadecyl ester PA0 3,5-di-tert-butyl-4-hydroxybenzyl-phosphoric acid monoethyl ester, calcium-salt PA0 4-hydroxy-lauric acid anilide PA0 4-hydroxy-stearic acid anilide PA0 2,4-bis-octylmercapto-6-(3,5-tert-butyl-4-hydroxyanilino)-s-triazine PA0 octyl-N-(3,5-di-tert-butyl-4-hydroxyphenyl)-carbamate PA0 methanol PA0 octadecanol PA0 1,6-hexanediol PA0 neopentyl glycol PA0 thiodiethylene glycol PA0 diethylene glycol PA0 triethylene glycol PA0 pentaerythritol PA0 tris-hydroxyethyl isocyanurate PA0 di-hydroxyethyl oxalic acid PA0 diamide PA0 methanol PA0 octadecanol PA0 1,6-hexanediol PA0 neopentyl glycol PA0 thiodiethylene glycol PA0 diethylene glycol PA0 triethylene glycol PA0 pentaerythritol PA0 tris-hydroxyethyl isocyanurate PA0 di-hydroxyethyl oxalic acid PA0 diamide PA0 N,N'-di-(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylenediamine PA0 N,N'-di-(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)trimethylenediamine PA0 N,N'-di-(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine
U.S. Pat. No. 3,933,946 describes N-hydroxy-N-phosphonomethylglycine esters which are useful as herbicides and plant growth regulators.
The use of hydroxyaminomethylphosphonates as stabilizers for organic materials is not described or suggested in the prior art. Additionally the compounds of formula I where R.sub.4, R.sub.5 and R.sub.6 are alkyl having at least 12 carbon atoms are novel. The instant compounds where R.sub.1 is a substituted silyl moiety are also novel.